i think i have a faulty CPU sensor on the motherboard.
The CPU sensor in the motherboard tab only showed when very hot. then i found out i can enable sub zero temp readings in HWInfo. with that enabled the sensor shows up every time i start HWInfo.
but the reading is -62c. when it gets hot it seems to climb to 60-65c. when it cools it jumps from 39c to -62c every time. it can not show idle temp and takes quite a while to rise.
As a result when the motherboard fan controller is on default, its set to monitor "CPU Temp" and therefore is not working correctly. luckily it has a setting monitor Tctrl on the cpu itself.

also i can set the debug numbers to show temperature. they are stuck on "33" (when hwinfo reports -62c) but as soon as temps in hwinfo are in the positive it seems to show the same.

i have a complete log, and enabled hwinfo debug earlier today. can i upload this here?

Thanks. You don't need to read that file, it's for me to analyze the system in more detail if there are issues.
So I checked it and HWiNFO didn't have proper support for your mainboard model yet. The CPU temperature reported under the Nuvoton sensor is not valid - ASRock changed this in the X470 series. I will fix this in the next HWiNFO Beta build (along with additional values for your mainboard). The only valid CPU temperature there is the "CPU (Tctl/Tdie)" and the other CPU sensor will report the same value once fixed.

Martin, you are my hero! thank you very much!
and btw HWInfo is the best tool for hardware monitoring! just found it recently!

do you know the YT channel "actually hardware overclocking"? have you seen builzoids video on the x470 master sli? he has some issues with VRM temp sensor... if it gets too hot it shows 0 for him. he also uses HWInfo64.

Thank you
I just checked that video and I see the highest VRM temperature it reached was 125 C. HWiNFO has an internal filter for some temperature values, which converts the 126-128 C values into 0 C, because such values are usually returned by sensors which are not connected, or provide erratic readouts. So the sensor has probably reached a value in that range. If it would be even higher (> 128 C) then the correct value would be shown.
They will also need to update HWiNFO to get more accurate sensor values for X470 ASRock series.

its working now! but seems very simmilar to the core temp, nearly mirroring the core temp when rise and falling.
thanks a lot for explaining too! you could also comment on youtube if it would clear things up!

thanks again for this wonderful piece of software! and thank you even more that its freeware, hope you can keep it that way! asrock support took 3 days to answer my mail, and suggestet cmos reset...